We had already
attained a depth of six thousand feet beyond that hitherto reached by
the foot of man, such as the mines of Kitz Bahl in Tyrol, and those
of Wuttembourg in Bohemia.

The temperature, which ought to have been 81° (178° Fahr.) was
scarcely 15° (59° Fahr.). Here was cause for reflection.

CHAPTER XIX.

GEOLOGICAL STUDIES IN SITU

Next day, Tuesday, June 30, at 6 a.m., the descent began again.

We were still following the gallery of lava, a real natural
staircase, and as gently sloping as those inclined planes which in
some old houses are still found instead of flights of steps. And so
we went on until 12.17, the, precise moment when we overtook Hans,
who had stopped.

"Ah! here we are," exclaimed my uncle, "at the very end of the
chimney."

I looked around me. We were standing at the intersection of two
roads, both dark and narrow. Which were we to take? This was a
difficulty.

Still my uncle refused to admit an appearance of hesitation, either
before me or the guide; he pointed out the Eastern tunnel, and we
were soon all three in it.

Besides there would have been interminable hesitation before this
choice of roads; for since there was no indication whatever to guide
our choice, we were obliged to trust to chance.

The slope of this gallery was scarcely perceptible, and its sections
very unequal. Sometimes we passed a series of arches succeeding each
other like the majestic arcades of a gothic cathedral. Here the
architects of the middle ages might have found studies for every form
of the sacred art which sprang from the development of the pointed
arch. A mile farther we had to bow or heads under corniced elliptic
arches in the romanesque style; and massive pillars standing out from
the wall bent under the spring of the vault that rested heavily upon
them. In other places this magnificence gave way to narrow channels
between low structures which looked like beaver's huts, and we had to
creep along through extremely narrow passages.

The heat was perfectly bearable. Involuntarily I began to think of
its heat when the lava thrown out by Snæfell was boiling and working
through this now silent road. I imagined the torrents of fire hurled
back at every angle in the gallery, and the accumulation of intensely
heated vapours in the midst of this confined channel.

I only hope, thought I, that this so-called extinct volcano won't
take a fancy in his old age to begin his sports again!

I abstained from communicating these fears to Professor Liedenbrock.
He would never have understood them at all. He had but one idea -
forward! He walked, he slid, he scrambled, he tumbled, with a
persistency which one could not but admire.

By six in the evening, after a not very fatiguing walk, we had gone
two leagues south, but scarcely a quarter of a mile down.

My uncle said it was time to go to sleep. We ate without talking, and
went to sleep without reflection.

Our arrangements for the night were very simple; a railway rug each,
into which we rolled ourselves, was our sole covering. We had neither
cold nor intrusive visits to fear. Travellers who penetrate into the
wilds of central Africa, and into the pathless forests of the New
World, are obliged to watch over each other by night. But we enjoyed
absolute safety and utter seclusion; no savages or wild beasts
infested these silent depths.

Next morning, we awoke fresh and in good spirits. The road was
resumed. As the day before, we followed the path of the lava. It was
impossible to tell what rocks we were passing: the tunnel, instead of
tending lower, approached more and more nearly to a horizontal
direction, I even fancied a slight rise. But about ten this upward
tendency became so evident, and therefore so fatiguing, that I was
obliged to slacken my pace.